25 year experiment shows ants can break down minerals, sequester CO2

And that reaction pulls carbon dioxide out of the atmosphere.

If you want a role model for work ethic in the animal kingdom, you’d do well to pick the ant. Maintaining tunnels, gathering food, and defending the colony are all in a solid day’s work. Now you might be able to cross off another item on the ant to-do list: pulling carbon dioxide out of the atmosphere.

Over geologic timescales, the Earth has a convenient regulator on its thermostat: the weathering of many minerals. During their breakdown, they react with carbon dioxide, which converts them into a clay mineral while also producing carbonate. In a warmer climate, weathering ramps up, removing more CO2 from the atmosphere. This provides a cooling influence. In a cooler climate, weathering slows and CO2 can accumulate in the atmosphere, nudging temperatures upwards.

Some of this is simply the result of physical weathering of exposed rock at the surface, but living organisms contribute as well. Tree roots penetrate cracks and pry rocks apart. Lichens and fungi in soil slowly dissolve rock. Burrowing things move material around.

Quantifying the influence of biology is a real challenge. Some things, like vegetation, have been studied but we remain ignorant about the weathering work done by many other organisms. Among the ones we've been ignorant about? Ants.

Arizona State’s Ronald Dorn has made a career studying weathering. Before that career started, he got some advice. “Luna Leopold was a famous geomorphologist at Cal Berkeley when I was a master’s student,” Dorn told Ars. “I had a couple of classes form Luna, and he urged us all to start baseline experiments when we started a new job as faculty. He said that geomorphology has few such long-term data gathering projects and that it would be important.”

So a little over 25 years ago, he crushed up a batch of Hawaiian basalt into fresh sand and found interesting places to bury it. That included sites in the Catalina Mountains of Arizona and at Palo Duro Canyon in Texas. The basalt sand went into half-meter holes augered into a variety of environments including bare ground, tree roots, and ant nests—with sand left in an open plastic pipe as a baseline.

Every five years, Dorn collected samples of the sand. With 25 years of samples in hand, he analyzed the amount of weathering the sand grains had undergone by throwing them under an electron microscope and calculating the amount of dissolution that had taken place. Because the weathering reaction also produces carbonate, the amount of carbonate was also measured at each location.

To Dorn’s surprise, the material from the ant nests stood out. Sand placed among tree roots experienced about 10 to 40 times as much weathering as the baseline grains, confirming that trees and their symbiotic fungi help break down minerals. In the ant nests, however, weathering was more like 50 to 175 times the baseline. Yet samples from termite nests were at the low end of the tree root range.

The ant nests also accumulated carbonate over time, while the bare ground sites didn’t. That could corroborate the high rate of weathering, but it’s also possible that other chemistry going on inside the nest contributes to carbonate formation.

Nobody has really studied mineral weathering in ant nests before, so we don’t actually know how this accelerated weathering is being accomplished. About all we can say is that ants do move bits of soils to and fro, which would mix the sand grains around. Dorn notes that these ants seem to be doing exactly what we would like to do—convert atmospheric carbon dioxide into minerals underground. It’s possible that the ants may have some tips for us if we could learn what’s going on in those nests.

Dorn also notes, very speculatively, that ants diversified and multiplied over the same time period that atmospheric CO2 declined from the hot climate of the dinosaurs into the ice age of the last few million years. Given their prodigious talents for weathering, it’s at least possible that ants had a little something to do with it.

Once upon a time, there was an ant and a grasshopper.All summer long, the ant worked hard.The grasshopper, he played the violin.He dance.Winter come.The ant grow fat.The grasshopper is cold.The grasshopper eats the ant.

So maybe they just passed a new carbon-neutral law through their inter-anthill ant-congress and their ant-EPA devised this cool carbon-capture method..I think they did that because the previous ant-cap-and-trade policy was not working...That's because the ant-lawyers for the developed anthills managed to place too much burden on developing anthills..More soon on aNtPR...

This is the second article I've read in a week that implies the atmosphere is a self-cleaning, homeostatic process (The other one was some numph about hydroxyl).

Have the global warming deniers changed tactics? Instead of denying the evidence, now they're all claiming, "ah don't worry about it, mama nature's got it covered. Step on the gas!"

Will complacency work where conspiracy failed? More than likely...

One doesn't need to be a global warming denier to see the importance of studying the various feedback systems in the climate. Clearly there are many and, as shown here, they are not all completely understood. A proper understanding of these (at least the major ones) is essential if our models are to be accurate. Today, it would be much easier to win support for change if the models anticipating a continuation of the warming trend in the nineties had been able to anticipate the (maybe completely unrelated) conditions which slowed that trend.

Before that career started, he got some advice. “Luna Leopold was a famous geomorphologist at Cal Berkeley when I was a master’s student,” Dorn told Ars. “I had a couple of classes form Luna, and he urged us all to start baseline experiments when we started a new job as faculty. He said that geomorphology has few such long-term data gathering projects and that it would be important.”

This will have interesting implication on building science. Basalt mineral wool is popular among green building crowd over fiberglass/XPS/EPS. Because it reduced the need for fossil resources, and re-use slags from the steel production.(Beside superior durability, fire resistance, soundproofing, etc.) And the assumption that:

Without knowing the baseline, it hard to say how much basalt rocks had been siphoned off by ants. Home owners are more concerned about termites than ants anyway. Plus the spun wool may be harder for ants to access than those grounded into sand grains. With 2"-6"(45mm-150mm) being typical recommended thickness for installation, I don't think it would be an issue for above grade wall application with the expected service life of 30-60 years. Any issues that developed will be discovered when the sidings are replaced. But for below grade usage as drainage control like this product, that with recommended installation as thin as 1 inch, would be more troubling, as they are rarely inspected if at all. Maybe that should be the doctoral thesis for one of his students. Digging up old below grade basalt mineral wool installations and see what ants had done to them.

The article mentions ant based weathering as compared to other weathering mechanisms, but does not compare them to the current rate we are adding CO2 to the atmosphere. I suspect that the amount of carbon captured by weathering is only a tiny fraction of what is currently being returned to the atmosphere. Especially considering it took millions of years to put those hydrocarbons under the ground in the first place.

"Dorn notes that these ants seem to be doing exactly what we would like to do—convert atmospheric carbon dioxide into minerals underground. It’s possible that the ants may have some tips for us if we could learn what’s going on in those nests."